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#1af65c61-6f55-416a-92f0-7ecbcfb6733a中等解答题等比数列的概念与通项数列

14.(1)已知{an}\{a_{n}\}是等比数列,a1=2a_{1}=2a4=16a_{4}=16.求{an}\{a_{n}\}的通项公式;
(2)已知数列{an}\{a_{n}\}的前nn项和为SnS_{n},若Sn=n2+nS_{n}=n^{2}+n(nN,n1)(n\in N,n\geqslant 1)ana_{n}